diff --git a/packages/experimental/cua/native/README.txt b/packages/experimental/cua/native/README.txt
index 8ad7032663..7636fe0a50 100644
--- a/packages/experimental/cua/native/README.txt
+++ b/packages/experimental/cua/native/README.txt
@@ -30,7 +30,7 @@ Element clicks prefer advertised AX actions and otherwise use pointer delivery.
 
 The responsible host/helper needs macOS Accessibility permission for AX state and input, and Screen Recording permission for screenshots. Capability preflight and permission errors do not grant permissions. Capture refuses a window that moves or resizes while the image is being read. Unassociated system panels and accessory-only applications are not selectable.
 
-Use `swift test --package-path packages/experimental/cua/native` for offline unit checks and `python3 packages/experimental/cua/native/tests/protocol_e2e.py` for JSONL admission, ordered replies and EOF shutdown without desktop operations. All Python native checks accept `--helper` to select a separately built comparison binary.
+Use `python3 packages/experimental/cua/native/tests/test_swift.py` for offline unit checks with the selected Apple toolchain’s Swift Testing framework/runtime paths and `python3 packages/experimental/cua/native/tests/protocol_e2e.py` for JSONL admission, ordered replies and EOF shutdown without desktop operations. All Python native checks accept `--helper` to select a separately built comparison binary.
 
 Run `python3 packages/experimental/cua/native/tests/axless_e2e.py` after building and unlocking the Mac to verify an owned window whose application removes and later restores its AX roots. The check requires existing Accessibility/Screen Recording grants, rejects stale element indices, captures the AXless window, verifies a coordinate click in the fixture state file, and checks restoration. It never changes system permission settings.
 
diff --git a/packages/experimental/cua/native/Sources/CuaNative/AXAccess.swift b/packages/experimental/cua/native/Sources/CuaNative/AXAccess.swift
index e12a6d96b8..eeb8bc5f4b 100644
--- a/packages/experimental/cua/native/Sources/CuaNative/AXAccess.swift
+++ b/packages/experimental/cua/native/Sources/CuaNative/AXAccess.swift
@@ -61,7 +61,7 @@ final class AXAccess {
     }
     func elementValue(_ value: CFTypeRef, _ name: String) throws -> AXUIElement {
         guard CFGetTypeID(value) == AXUIElementGetTypeID() else { throw NativeFailure(code: "NATIVE_ERROR", message: "Accessibility \(name) is not an element") }
-        return unsafeBitCast(value, to: AXUIElement.self)
+        return unsafeDowncast(value, to: AXUIElement.self)
     }
     func element(_ element: AXUIElement, _ name: String) throws -> AXUIElement? {
         guard let value = try attribute(element, name) else { return nil }
@@ -123,8 +123,8 @@ final class AXAccess {
     func bounds(_ element: AXUIElement) throws -> WindowBounds? {
         guard let position = try attribute(element, "AXPosition"), let size = try attribute(element, "AXSize") else { return nil }
         guard CFGetTypeID(position) == AXValueGetTypeID(), CFGetTypeID(size) == AXValueGetTypeID() else { return nil }
-        let positionValue = unsafeBitCast(position, to: AXValue.self)
-        let sizeValue = unsafeBitCast(size, to: AXValue.self)
+        let positionValue = unsafeDowncast(position, to: AXValue.self)
+        let sizeValue = unsafeDowncast(size, to: AXValue.self)
         var point = CGPoint.zero
         var dimensions = CGSize.zero
         guard AXValueGetValue(positionValue, .cgPoint, &point), AXValueGetValue(sizeValue, .cgSize, &dimensions),
diff --git a/packages/experimental/cua/native/Sources/CuaNative/AXWorker.swift b/packages/experimental/cua/native/Sources/CuaNative/AXWorker.swift
index e2e484ea97..d85461ccdb 100644
--- a/packages/experimental/cua/native/Sources/CuaNative/AXWorker.swift
+++ b/packages/experimental/cua/native/Sources/CuaNative/AXWorker.swift
@@ -183,9 +183,7 @@ actor AXWorker {
             try NativePlatform.requireAccessibility()
             if let window { _ = try NativePlatform.ownedWindow(identity.pid, window) }
             try cancellation.check()
-            let observedWindows: [WindowInfo]
-            if let window { observedWindows = [try NativePlatform.ownedWindow(identity.pid, window)] }
-            else { observedWindows = NativePlatform.windows().filter { $0.pid == identity.pid } }
+            let observedWindows = NativePlatform.windows().filter { $0.pid == identity.pid }
             let id = try identifier("snapshot")
             let scope = SnapshotScope(appHandle: handle, windowID: window)
             snapshots[scope] = NativeSnapshot(id: id, scope: scope, elements: projection.indexed)
diff --git a/packages/experimental/cua/native/tests/test_swift.py b/packages/experimental/cua/native/tests/test_swift.py
new file mode 100644
index 0000000000..b39e18b4e6
--- /dev/null
+++ b/packages/experimental/cua/native/tests/test_swift.py
@@ -0,0 +1,27 @@
+"""Run Swift Testing with the selected Apple toolchain's runtime search paths."""
+import subprocess
+import sys
+from pathlib import Path
+
+
+def main():
+    compiler = Path(subprocess.check_output(["xcrun", "--find", "swift"], text=True).strip())
+    package = Path(__file__).resolve().parents[1]
+    command = [str(compiler), "test", "--package-path", str(package),
+               "--disable-xctest", "--enable-swift-testing"]
+    # Command Line Tools ships these libraries outside SwiftPM's default search
+    # paths. Full Xcode and other selected toolchains keep their normal lookup.
+    framework_root = compiler.parents[2] / "Library/Developer/Frameworks"
+    if (framework_root / "Testing.framework").is_dir():
+        command += ["-Xswiftc", "-F", "-Xswiftc", str(framework_root),
+                    "-Xlinker", "-F", "-Xlinker", str(framework_root),
+                    "-Xlinker", "-rpath", "-Xlinker", str(framework_root)]
+        runtime = framework_root.parent / "usr/lib"
+        if (runtime / "lib_TestingInterop.dylib").is_file():
+            command += ["-Xlinker", "-rpath", "-Xlinker", str(runtime)]
+    command += sys.argv[1:]
+    raise SystemExit(subprocess.call(command))
+
+
+if __name__ == "__main__":
+    main()
diff --git a/packages/experimental/cua/package.json b/packages/experimental/cua/package.json
index 37ebaa9883..a3d2c93a50 100644
--- a/packages/experimental/cua/package.json
+++ b/packages/experimental/cua/package.json
@@ -36,6 +36,7 @@
     "native/Package.swift",
     "native/Sources",
     "native/tests/swift",
+    "native/tests/test_swift.py",
     "native/LICENSE.cua-driver",
     "native/upstream.json",
     "native/README.txt",
diff --git a/scripts/check-workspace-constraints.ts b/scripts/check-workspace-constraints.ts
index cea64bbe99..5fad97bb35 100644
--- a/scripts/check-workspace-constraints.ts
+++ b/scripts/check-workspace-constraints.ts
@@ -175,7 +175,7 @@ export function readWorkspaceManifests(repositoryRoot: string): WorkspaceManifes
 
 const packageFileExtras: Readonly<Record<string, readonly string[]>> = {
   // CUA publishes its client API and attributed native source for local macOS builds.
-  '@deepseek-ai/dsh-experimental-cua': ['lib/api.js', 'lib/bridge.js', 'native/Package.swift', 'native/Sources', 'native/tests/swift', 'native/LICENSE.cua-driver', 'native/upstream.json', 'native/README.txt', 'native/protocol.schema.json'],
+  '@deepseek-ai/dsh-experimental-cua': ['lib/api.js', 'lib/bridge.js', 'native/Package.swift', 'native/Sources', 'native/tests/swift', 'native/tests/test_swift.py', 'native/LICENSE.cua-driver', 'native/upstream.json', 'native/README.txt', 'native/protocol.schema.json'],
   // Owned Worker bundles import this public bootstrap before their business entry.
   '@deepseek-ai/dsh-app-boot': ['lib/worker/profile-resolution-bootstrap.js'],
   // Statically linked client libraries keep their stylesheets next to the emitted